Work out how hot it actually feels when humidity is added to the air temperature.
Feels like40.4 °C (105 °F)
Risk levelDanger
Heat exhaustion likely; heatstroke likely with continued activity.
How humidity makes heat dangerous
Your body cools itself by evaporating sweat. The more moisture the air already holds, the slower that evaporation runs, so the same air temperature feels far hotter and your body struggles to shed heat. That is why 32 °C at 20% humidity is uncomfortable while 32 °C at 80% humidity can be genuinely dangerous.
In high heat, drink before you feel thirsty, move activity to early morning or evening, wear loose light clothing, and take breaks in the shade. Children, older people and anyone on medication that affects sweating are at higher risk at the same heat index.